Polymers, their preparation and their use

ABSTRACT

(Co)poly-α-hydroxyacrylic-acid-based polymers (P), optionally in lactonized form or in salt form, optionally as Mg-complexes, and which are characterized by a content in carbohydrate units and 2-hydroxy-2-carboxyethylene-1,2 monomer units, are suitable as biologically degradable, alkali-resistant stabilizers for peroxide bleaching agents.

In peroxide bleaching of fibrous material, in particular of cellulosicfibrous material, for increasing the bleaching yield, i.e. in order toavoid a premature decomposition of the peroxide bleaching agent—beforeall hydrogen peroxide—there are employed stabilizers, which may beformulated as stock solutions and before all for continuous bleachingprocesses, also as reinforcing liquors. Depending on the process thereinforcing liquors may be of a different alkalinity and may also bevery strongly alkaline, e.g. of an alkalinity that corresponds to 0.2Nto 8N NaOH. For the employed stabilizer it is desired that they bestable also at high alkalinities. Since the stabilizers are employedonly as adjuvants, i.e. shall not build up or shall build up only in alabile way on the substrate and are finally present in the backwater, itis thus desired that these adjuvants be biologically degradable.

From U.S. Pat. No. 4,363,699 it is known to bleach textile material orpaper with hydrogen peroxide under alkaline conditions in the presenceof certain sodium polya-hydroxyacrylates. In U.S. Pat. No. 4,916,699there are described poly-α-hydroxyacrylates of high stability to alkali,which may also be formulated in alkaline stock solutions and reinforcingliquors. In DE-A43 44 029 there are described copolymers that derivefrom certain mono- or disaccharides and certain unsaturated sulphonicacids or dicarboxylic acids and monoethylenically unsaturatedC₃₋₁₀-carboxylic acids (there are named acrylic acid and methacrylicacid) or from certain mono- or disaccharides and acrylic acid, asdispersants and cobuilders or sequestrants. These copolymers do not havea sufficient stabilizing activity on peroxy bleaching agents (this meansthat in the course of the bleaching process the peroxide decompositionprovoked by the alkali cannot be sufficiently hemmed by them, so that asubstantial proportion of the peroxide is decomposed prematurely, i.e.long before completion of the bleaching process, and thus cannot displayits bleaching activity), and thus for the peroxide bleaching it isrecommended to combine the copolymer with stabilizers for percompounds.However, it is also possible to bleach with a peroxide without using astabilizer, but the use of a stabilizer increases significantly theyield by avoiding premature decomposition of the peroxide, which is ofparticular importance in alkaline peroxide bleaching liquors, especiallyin more concentrated alkaline peroxide bleaching liquors, such as thoseused in padding processes.

It has now been found, that the below defined polymers (P), whichcontain the monomer units (a) and (s), while the presence of costlysulphogroup-containing monomer units is not necessary, meet surprisinglywell the above requirements, namely not only with reference tobiological degradability but also as for stability, especially understrongly alkaline conditions, e.g. at ≧0.2N NaOH, or even ≧0.5N NaOH,principally ≧2N NaOH, and efficiency for the stabilizing of peroxycompounds in the alkaline peroxide bleaching (in particular in paddingliquors and in stock solutions), namely also without the presence ofadditional sequestrants or other stabilizers.

The invention relates to the polymers (P), their production and use, aswell as to the corresponding (P)-containing compositions and alkalinestock solutions as are suitable for bleaching liquors, and to thecorresponding (P)-containing bleaching liquors.

A first object of the invention is, thus, a(co)poly-α-hydroxyacrylic-acid-based polymer (P), optionally inlactonized form or in salt form, which is characterized by a content in

(s) at least one carbohydrate unit and

(a) at least one 2-hydroxy-2-carboxyethylene-1,2-unit,

or a mixture of such polymers (P).

The polymers (P) of the invention are obtainable by polymerisation of atleast one vinyl monomer (A), which provides the monomer units (a) andwhich is principally an a-halogenacrylic acid or a salt thereof, andoptionally at least one further vinyl monomer (B), in the presence of atleast one optionally modified carbohydrate (S), which provides the unit(s), and optionally reaction of the polymerisation product with at leastone base for salt formation.

The units (a) correspond in the non-lactonized acid form to the formula

as occur e.g. in poly-α-hydroxyacrylic acids (and therefore are alsocalled “α-hydroxyacrylic acid units”). Optionally a carboxylic group in(a) may be lactonized with a suitable hydroxy group or it may be presentin salt form.

As vinyl monomers (A) there may be employed monomers which in theirpolymerisation lead to corresponding 2-hydroxy-2-carboxyethylene-1,2units, principally α-Hal-acrylic acid, wherein Hal signifies chlorine orbromine, i.e. α-chloroacrylic acid or α-bromoacrylic acid, or ahydrosoluble salt thereof. Preferably as (A) there is employed (A₁),i.e. α-chloroacrylic acid optionally in salt form. If desired there maybe employed a precursor of (A₁), e.g. α,β-dichloropropionic acid or afunctional derivative thereof (e.g. methylester or chloride), whichbefore the polymerisation to (A₁) is dehydrochlorinated and, ifrequired, saponified.

As further vinyl monomers (B), come into consideration mainly lowmolecular anionic or non-ionic monomers, in particular (B₁), i.e.α,β-ethylenically unsaturated aliphatic carboxylic acids containingpreferably 3 to 6 carbon atoms, e.g. acrylic acid, methacrylic acid,maleic acid, itaconic acid, aconitic acid, fumaric acid or citraconicacid.

The monomers (A) and (B), in particular (A₁) and (B₁), may be employedin the form of the free acids or, preferably, at least in part in theform of a hydrosoluble salt, and if they are employed as salts, theseare transformed to the acid form in the acidic reaction medium. Theremay e.g. be employed ammonium salts or preferably alkali metal salts(e.g. Li-, Na- or K-salts), with particular preference sodium salts ofthe mentioned monomers. The monomers (A) and (B), in particular (A₁) and(B₁) are advantageously employed in such quantitative ratios that (A)amounts to at least 50 mol-%, i.e. to 50 to 100 mol-% of [(A)+(B)],respectively so that (a) amounts to 50 to 100 mol-% of [(a)+(b)], inwhich (b) are the monomer units introduced by reaction with (B).Advantageously the proportion of (A) is 80 to 100 mol-%, with particularpreference 100 mol-% of [(A)+(B)], respectively the proportion of (a)amounts advantageously to 80 to 100 mol-%, preferably 100 mol-% of[(a)+(b)], i.e. preferably there is employed no (B).

As optionally modified carbohydrates (S) come into consideration anysuch compounds containing at least three carbon atoms and having polyolcharacter, i.e. containing at least three hydroxy groups per carbonchain or ring, and which are soluble, suspendable or swellable in water.As (S) there are principally meant natural saccharides or modificationproducts thereof, i.e. saccharides that are obtained from animal orvegetable products (e.g. from the processing of milk, honey or parts ofplants) or simple modification products thereof, e.g. enzymatically orchemically modified products (e.g. by hydrolysis, by hydrogenation, byoxidation, by partial etherification or esterification and/or byderivatisation), so long as the essential polyol character of thesaccharide is maintained. However, it is also possible to employsynthetic saccharides, principally polymerisation products of mono-or/and disaccharides as are producible by polymerisation in aqueoussolution, but preferably the saccharides (S) are natural saccharides orsimple modification products thereof.

As carbohydrates (S) come advantageously into consideration mono-,oligo- or polysaccharides, whose monomer units contain 4 to 7,preferably 5 or 6 carbon atoms. As modified carbohydrates (S) comeprincipally into consideration those carbohydrates in which one ot twofunctional groups have been chemically modified, e.g. by reduction topolyols or desoxysugars, by oxidation to mono- or dicarboxylic acids, orby alkylation e.g. with unsubstituted or substituted low molecularalkyl, principally alkylation with unsubstituted C₁₋₄-alkyl, inparticular methyl or butyl, by carboxyalkylation, mainlycarboxymethylation (e.g. by reaction with choloracetic acid), byaddition of epoxides (e.g. ethylene oxide) to oxyalkylation products, orby reaction with optionally substituted chlorohydrins, or by acylation,e.g with acyl radicals of low molecular carboxylic acids, principally ofC₂₋₄-carboxylic acids, in particular acetyl, or by derivatizing, so longas there are present at least three hydroxy groups with carbohydratecharacter per carbon chain or ring.

As (S) come into consideration any mono-, oligo- or polysaccharides orsimple modification products thereof or mixtures thereof, in particular

(S₁) monosaccharides,

(S₂) oligosaccharides,

(S₃) polysaccharides and

(S₄) modified saccharides.

As (S₁) are suitable e.g. C₄₋₆-monosaccharides, such as e.g. erythrose,threose, xylose, ribose, arabinose, lyxose, glucose, mannose, gulose,galactose, fructose, allose, altrose, idose, talose, and mixturesthereof. As (S₂) are suitable open-chain or cyclic oligosaccharides,such as e.g. lactose, maltose, cellobiose, raffinose, gentiobiose,trehalose, melezitose, dextrines and cyclodextrines (α, β and/or γ) andmixtures thereof. As (S₃) are suitable any polysaccharides that aresoluble, suspendable or swellable in water, principally starchpolysaccharides, e.g. (S₃₁) substantially linear polysaccharidesoccurring in starches, in particular amylose and degradation products(preferably hydrolysis products) thereof, e.g. sirup or dextrines, aswell as mixtures of such polysaccharides, and (S₃₂) substantially linearother polysaccharides and branched polysaccharides, e.g. cellulose,xylanes, arabanes and galactanes. Optionally the polysaccharides may beat least partially enzymatically or acid-hydrolytically modified, e.g.degraded, (e.g. to oligosaccharides). As (S₄) are suitable simplymodified saccharides (mono- or preferably oligo- or polysaccharides),principally reduction products of mono- or oligosaccharides tocorresponding polyols or desoxy sugars, oxidation products to carboxylicacids, acylation products or alkylation products, or also naturallyoccurring carboxylic acids, polyols, alkyl substituted saccharides orother derivatives, e.g. sulpho group-containing saccharides. As (S₄)come principally into consideration the following modified saccharides:(S₄₁) simple polyols, e.g. alditoles, preferably C₅₋₆-polyols, e.g.sorbite or mannite, (S₄₂) alkyl-substituted saccharides, e.g. inositolsand alkylglykosides, e.g. butyl- or methylglucosides, (S₄₃) carboxylicacids, optionally in salt form, principally aldonic- or uronic acids,e.g. gluconic acid, gulonic acid, glucoheptonic acid, glucuronic acid,and alginic and pectic acids and their partial decarboxylation products,and (S₄₄) other saccharide derivates, e.g. sulphate-containing naturalproducts, acylated saccharides, saccharides alkylated with substitutedalkyl (e.g. carboxyalkylated, oxyalkylated or reacted with optionallysubstituted chlorohydrins), modified pectines or derivatisedpolysaccharides. As pectines come in general into consideration knownpectines, e.g. from fruit peel or principally such as occur in starches,e.g. in native starch flours and enzymatically modified derivativesthereof, e.g. enzymatically fluidified derivatives of pectines fromstarches, or also synthetic amylopectine.

The polysaccharides (S₃), principally the starch polysaccharides (S₃₁),may be modified in a manner conventional per se with known enzymes, e.g.with hydrolases, principally glycoside hydrolases, in particular withamylases, preferably α-amylases, or/and may be modified by acidhydrolysis, advantageously by the action of strong mineral acids,preferably sulphuric, phosphoric or hydrochloric acid, or strongcarboxylic acids, preferably citric, formic, acetic, phthalic andbenzoic acid.

With particular advantage there are employed as (S) for the polymers (P)of the invention starch components as conventionally occurring in starchflours (e.g. as obtained from parts of plants such as legumes, cereals,tubers, palm mellow or algae), e.g. rice starch, corn starch, potatostarch, tapioca starch, soybean starch, guaran, carragheen, carob beangum, agar or ghatti gum and mixtures thereof.

According to an advantageous feature of the invention, there areemployed as (S) (S′) i.e. technical, optionally purified or/andenzymatically modified starches, e.g. in the form of starch flours.

The process of the invention for the production of the polymers (P)takes place under acidic conditions and leads first to an acid polymer(P1), which by reaction with a base may be transformed to thecorresponding salt form (P2).

The process for the production of the acid polymer (P1) or of a mixturethereof is preferably characterized in that (A₁) and optionally (B₂) ispolymerized in aqueous acidic medium in the presence of (S), preferably(S₃), with particular preference (S₃₁).

The polymerisation takes place advantageously in aqueous medium and atpH-values which are advantageously ≦6, preferably ≦4, in particular inthe range of 0 to 6, preferably 0.1 to 4. The pH advantageously adjustedwith a strong mineral acid, e.g. phosphoric acid or preferably sulphuricacid or with a strong carboxylic acid, e.g. citric acid. Theconcentration of the monomers, i.e. (A) and optionally (B), and of thecomponents (S) may vary in a broad range and is expediently chosen sothat there is provided a true solution of (S₁) or a true or colloidalsolution of (S₂) or (S₄) or that (S₃) or (S₄) is in suspended orswollen, dispersed form or as a colloidal solution, and the mixture isstirrable. The (S)- and monomer-content of the reaction mixture is e.gin the range of 2 to 70% by weight, advantageously in the range of 5 to70% by weight, preferably 10 to 60% by weight. The reaction temperaturefor the polymerisation is mainly at values in the range of 20 to 150°C., advantageously 40 to 98° C., preferably 60 to 90° C. Thepolymerisation is substantially radicalic and takes place suitably underradical-forming conditions, e.g. in the presence of radical-forminginitiators or under the action of suitable irradiation of high energycontent, as can conventionally be employed for polymerisation for theproduction of poly-α-hydroxyacrylic acid. The following initiators orcatalysts come, in particular, into consideration: water soluble azocompounds [in particular 4,4′-azo-bis4-cyanopentanoic acid) or2,2′-azo-bis-(2-amino-dipropane)dihydrochloride], redox systems orperoxy-compounds (in particular diacetylperoxide, di-tert.butylperoxide,tertbutylhydroperoxide, tert.butylperpivalate, cumenehydroperoxide,benzoylhydroperoxide, dibenzoylperoxide, diisopropylperoxydicarboxylate,sodium perborate, hydrogen peroxide or ammonium- oralkalimetal-peroxydisulphate); it is also possible to employcerium(IV)-salts, such as cerium(IV)ammonium salts, e.g.cerium(M)ammonium sulphate, as initiators, preferably, however, thereare employed no cerium(IV)-compounds. Among the mentioned polymerisationinitiators the peroxy compounds are preferred, mainly ammonium- orpotassium-peroxydisulphates and hydrogen peroxide, before all hydrogenperoxide. The hydrogen peroxide may be employed as such or asH₂O₂-yielding compound, e.g. as potassium peroxide; preferably, however,there is directly employed H₂O₂. The amount of the initiators isexpediently chosen depending on the monomers, in particular on theconcentration of (A) and, if present, (B), and their molar ratio to (S).The molar ratio of the monomers (A) and (B) referred to (S) may range ina broad scope, suitably so that in the final product there is present onaverage at least one α-hydroxyacrylic acid unit for every carbohydratestarting molecule. Depending on the molecular weight of the carbohydratebackbone in the final product there may be employed for every mole oftotal monomers [(A)+(B)], in particular [(A₁)+(B₁)], advantageoulsy 20to 1000, preferably 30 to 500, in particular 40 to 300 g of totalhydroxycompounds (S). For every mole of carbohydrate unit (sI) in (S)there are employed advantageously 0.5 to 5, preferably 0.8 to 4, withparticular preference 1 to 3 moles or total monomers [(A)+(B)], inparticular [(A₁)+(B₁)]. As carbohydrate unit (si) in the optionallymodified starting carbohydrate (S) there is understood an open chain orpreferably cyclic, optionally modified carbohydrate group bearing forevery group of connected carbon atoms, at least three hydroxy groups assubstituents and, if it is cyclic, contains a (preferably furanoside orpyranoside) oxygen atom as a ring element, and where the units (s1) mayoptionally be joined to each other over oxygen (e.g. a glucoside ring asoccurring in oligo or polyglucosides). If hydrogen peroxide is used asan initiator, its concentration, referred to the monomers (A) and (B),is advantageously at least 1 g of H₂O₂ for every mole of [(A)+(B)], e.g.2 to 60 g of H₂O₂ or the equivalent amount of another peroxy catalyst.The respective reactants an d initiators and the acid may be added atonce or stepwise; a good reaction c ontrol may be achieved e.g. bystepwise addition of acid and initiator. The degree of polymerisation ofthe employed monomers (A) and (13) may be controlled, e.g. by means ofthe amount of peroxy initiator.

The enzymatic treatment, e.g. with an α-amylase, takes place e.g. atpH-values in the range of 5 to 8, at elevated temperature, e.g. in therange of 50 to 95° C., and at enzyme concentrations of 0.5 to 10 g/l.

An enzymatic treatment, e.g. of oligo- or polysaccharides orrespectively of pectines, may also precede the mentioned polymerisationin one process sequence in a same reaction vessel. The enzymaticreaction may then suitably be interrupted by addition of the mineralacid, e.g. at pH-values ≦4. Under the strongly acidic polymerisationconditions there may also be carried out a pre-determined degradation ofthe employed polysaccharides or pectines.

By the acidic polymerisation conditions there are formed at first theacid polymerisates (P1), in which the α-hydroxyacrylic acid units arepresent at least in part in lactonized form, and the little solublepolymerisation product is present in the acidic reaction medium as adiscontinuous phase, e.g. as a precipitate or in suspended form; by thesubsequent treatment with a base the optionally lactonizeda-hydroxyacrylic acid units, as well as any further carboxylic groups,are transformed to their salt form and in this also the respectivelactone rings are hydrolyzed, by this there is formed the polymer salt(P2).

For hydrolysis and salt formation there may be added suitable bases, ifdesired in aqueous form, e.g. ammonia, alkali metal hydroxides and/orlow molecular mono-, di- or tri-alkylamines or -alkanolamines [inparticular triethanolamnine or triisopropanolamine] and/or bufferingalkali metal salts, among which alkali metal hydroxides (lithium, sodiumor potassium hydroxide) are preferred, especially sodium hydroxide andpotassium hydroxide.

By the salt formation with the mentioned bases the less soluble polymers(P1), which contain the α-hydroxyacryeic acid units in optionallylactonized form and are formed e.g. in suspended form in the aqueousacidic medium, may be transformed into a more soluble salt form (P2), sothat there is formed a polymer solution.

If desired the obtained polymers may be derivatized, e.g. by reactionwith derivatizing reactants (C), preferably under basic conditions. Asderivatizing reactants (C) are suitable compounds known per se, mainlyalkylating agents e.g. halides (e.g. chloroacetic acid, chlorpropionicacid). The derivatizing reaction with (C) may be carried out in a mainerknown per se, if desired also in the same reaction medium, e.g. atpH-values in the range of 7.5 to 10—adjusted advantageously by additionof alkali metal hydroxide—and at elevated temperature, e.g. at 50 to 95°C.

The length and distribution of the (co)polymer chains may be conditionedby the choice of the weight ratios and reaction conditions. The polymers(P) may, thus, contain the units (a) and, if present, (b) built on or into form (co)polymers or/and graft polymers; in the case of an acidic(partial) hydrolysis of the saccharides (S) also (A) or respectively (B)may be built in or on in the respective place.

The molecular weight {overscore (M)}_(W) of the obtained polymers (P),referred to the sodium salt form of (P2), is e.g. in the range of 500 to1,000,000, advantageously 500 to 200,000, preferably in the range of 600to 60,000, in particular 600 to 12,000. The mentioned molecular weightsare intended as weight average. The polydispersity is advantageously <4.The molecular weight and the polydispersity may be determined by gelpermeation chromatography against normed polyacrylic acid standards.

The so-produced polymers are mostly obtained in aqueous form. Theseaqueous compositions are as such stable, especially in the abovementioned concentrations (e.g. 2 to 70% by weight, advantageously 5 to70% by weight, preferably 10 to 60% by weight), and may be handled so asthey have been produced, in particular they may be shipped and used, orthey may also, if desired, be dried, e.g. by spraying or granulating,after which for use they may be correspondingly diluted again withwater.

The polymers (P) find their use as adjuvants in the treatment of fibrousmaterial, in particular as stabilizers for the peroxide bleaching ofcellulose-containing fibrous material, and a further object of theinvention is a process for the peroxide bleaching ofcellulose-containing fibrous material in the presence of alkali and of astabilizer, which is characterized by the use of (P), preferably of(P2), as a stabilizer.

As alkali are suitable principally

(D) alkali metal hydroxides.

For use in the peroxide bleach it is of particular advantage to combine(P) respectively (P2) with magnesium ions, suitably by treating (P1) orpreferably (P2) with

(E) hydrosoluble magnesium salts,

e.g. with hydrosoluble magnesium salts of a mineral acid, preferablymagnesium chloride or sulphate, by which there are formed (P3), i.e.magnesium complexes or complex salts of (P) or respectively of (P2),which display a particularly pronounced stabilizing action in theperoxide bleach. A particular object of the invention are theMg-complexes (P3).

(P2) and/or (P3) are readily hydrosoluble and also compatible withalkalies; they may be dissolved in water and also in aqueous alkali, inparticular in aqueous alkali metal hydroxide solutions.

The polymers (P) of the invention, in particular (P2) and/or (P3), maybe advantageously formulated as aqueous concentrated compositions, thatcontain (P2) or respectively (P3) and optionally further additions, inparticular (E) as defined above, and/or

(G) a sequestrant which is different from (P),

preferably in the below described quantitative ratios. The (P2)- or(P3)-content in the concentrated aqueous compositions is e.g. in therange of 2 to 70, advantegeously 5 to 70, preferably 10 to 60% byweight, referred to (P2), the (E)-content is advantageously in the rangeof 0 to 20, preferably 0 to 10, in particular 0 to 6% by weight, the(G)-content is advantageously in the range of 0 to 50, preferably 0 to20, principally 0 to 10, in particular 0 to 4% by weight, the watercontent is advantageously ≧20% by weight, preferably ≧30% by weight.

For the bleaching process of the invention are suitable in general,conventional bleaching machines and systems,and conventional bleachingmethods as are, in general, employed for the alkaline bleaching ofcellulosic fibrous material from aqueous medium, before all in thetextile pre-treatment or in the working-up of grey paper. Beforeaddition into the bleaching liquor, the bleaching liquor components tobe employed are suitably formulated to stock solutions (also reinforcingliquors) containing the alkali (preferably NaOH) and the stabilizer (P),preferably (P2). If required, the stock solutions (respectivelyreinforcing liquors) may contain further additions as are to be employedfor the respective procedure, e.g. a hydrosoluble magnesium salt (E),e.g. magnesium chloride, for adjusting the water hardness or for formingMg complexes with (P), preferably with (P2),

(F) surfactants (in particular wetting agents)

and occasionaly also further substances, such as lubricants, otherpreferably low molecular sequestrants (G), optical brighteners a.s.o.,as are desired for the respective bleaching process. The peroxide (H)employed for the bleaching may also be present in the stock solution ormay be added separately to the liquor. In a particular feature of theprocess one or more of the mentioned components, with the exception ofthe peroxide, and in addition to (P) or respectively (P2), optionally inthe form of Mg-complex (P3), may be formulated as a concentrated aqueousstock or reinforcing solution and the peroxide may be added directlyinto the bleaching liquor or may also be admixed into the stock solutionshort before the addition into the bleaching liquor. If desired,however, the peroxide may also be already present, together with theremaining components, in the concentrated solutions.

A particular object of the invention are aqueous alkalinestabilizer-containing, preferably concentrated solutions, in particularstock solutions, which are characterized by a content of the components

(P) as defined above, preferably (P2) or (P3), and

(D) alkali metal hydroxide,

in particular those additionally containing at least one of thecomponents (E), (F) and (G); in particular, however, also thosecontaining

(H) a peroxide-based bleaching agent

in addition to the mentioned components.

A further object of the invention consists in employing in the bleachingprocess of the invention. The mentioned components in the form of thementioned stock solutions containing (P) and (D) as well as (E), (F)and/or (G) and optionally (H).

The mentioned concentrated aqueous solutions contain component (P),preferably as (P2) or (P3), advantageously in concentrations of 1 to 50g/l, preferably 1.4 to 35 gil [calculated as (P2) in the form Na-salt].

Component (D) is preferably KOH or in particular NaOH and isadvantageously present in concentrations of 5 to 350 g/l, e.g. 80 to 200g/l; with particular preference the concentration of the alkali metalhydroxide, in particular of the NaOH, is 0.2 to 8N, advantageously 0.5to 7 N, preferably 2 to 5N NaOH.

Component (E), which expediently is a salt suitable for complexformation, e.g. magnesium chloride, is—if present—advantageouslyemployed in such concentrations as are sufficient for achieving a waterhardness of the bleaching liquor of 3-10° dH, in particular 4-8° dH.

Component (F) may be required depending on the kind of the bleachingmethod, and has advantageously the character of a wetting agent, [e.g.of a detergent, if the bleaching is combined with a boiling-off of thetextile material, or it serves for the wetting of a dry substrateemployed in the bleaching bath]. Preferably the employed wetting agents(F) are non-ionogenic, anionactive or amphoteric. The non-ionogenicsurfactants are e.g. addition products of ethylene oxide and optionallypropylene oxide to corresponding alcohols, e.g. oxoalcohols or fattyalcohols with 8 to 18 (preferably 9 to 15) carbon atoms, and containe.g. on average 2 to 40 ethyleneoxy units per molecule. In theanionactive surfactant molecules the anionic radicals are advantageouslysulphate, sulphonate, phosphoric acid ester, phosphonate or carboxylicacid groups (e.g. soaps or carboxymethylation products of non-ionogenicsurfactants), the corresponding lipophilic radicals contained in theanionactive surfactants are mainly aliphatic or araliphatic hydrocarbonradicals with 10 to 24 carbon atoms; optionally the anionactivesurfactants may contain alkyleneoxy units, in particular ethyleneoxy orpropyleneoxy (e.g. 1 to 30 ethyleneoxy groups). The anphotericsurfactants may e.g. be acid modified amines, where the lipophilicradicals may be those as mentioned above, among which the aliphatic onesare preferred, the molecule may optionally contain alkyleneoxy units andthe amino groups may optionally be quatemized. Among the mentionedsurfactants (F) the non-ionogenic ones and the anionactive ones arepreferred. The concentration of the surfactants depends on theparticular bleaching process and may e.g. range in the scope of 0.1 to10 g of surfactant per liter of stock solution.

As component (G) are principally suitable low molecular sequestrants,especially carboxylic- or phosphonic-acid-group-containing aminocompounds, in particular carboxymethylated or phosphono-methylatedaliphatic di- or tri-amines or ammonia, e.g. nitrilotriacetic acidsodium salt, ethylenediaminetetraacetic acid sodium salt,diethylenetriaminepentacetic acid sodium salt,dipropylenetriaminepentaacetic acid sodium salt anddiethylenetriaminepentamethylphosphonic acid sodium salt, among whichnitrilotriacetic acid is preferred (i.a. also because ofbiodegradability). Also the above mentioned trialkanolamines, preferablytriethanolamin, may display in the compositions and liquors of theinvention a sequestering action and be employed as (G), especially if(P2) is present as alkali metal salt. The amount of component (G) mayrange in a broad scope and is advantageously not higher than theemployed amount of (P), or respectively (P2) or (P3). For every 100parts of (P), or respectively (P2), there are employed e.g. 0 to 100,advantageously 0 to 50, preferably 0 to 12 parts by weight of (G).

Component (H) may, as already mentioned, be given directly into thebleaching liquor or be admixed with the remaining stock solution, beforethe addtion into the bleaching liquor, or be present from the beginningin the stock solution. According to the invention, there are employedadvantageously for every 100 parts by weight of component (H), inparticular for every 100 parts by weight of H₂O₂, 1 to 100, preferably 2to 90, in particular 2 to 60 parts by weight of component (P)(calculated as sodium salt).

The process of the invention and the aqueous solutions of the inventionare suitable for any conventional bleaching process from aqueous medium,in which cellulosic fibrous materials are bleached with peroxycompounds, in particular with hydrogen peroxide, in the presence ofalkali, especially for the bleaching of textile material, mainly afterdesizing and before dyeing or finishing, preferably in the textilepretreatment. The process of the invention is of particular interest forthe semi-continuous and continuous bleaching of textile material widthsor textile yarns, in which the bleaching liquor is adjusted during thebleaching procedure to a constant composition by further feeding-in ofthe stock solution or optionally with reinforcing liquors and (withwater) to a constant level, e.g. according to hot bleaching, immersionbleaching or impregnation bleaching procedures. The process of theinvention and the stock solutions of the invention are particularlysuited for the last mentioned procedure.

For the production of the bleaching liquor and/or of the stock solutionsor reinforcing liquors, there are employed with particular advantage theabove concentrated compositons.

The bleaching conditions correspond in general to conventional bleachingprocedures, thus, e.g. the temperatures may range in the scope of 15 to180° C., preferably in the scope of from 40 to 120° C., the alkalinitycorresponds advantageously to a NaOH-concentration of 0.2 to 8%,preferably 0.3 to 5%, in particular 0.4 to 5%; the concentration ofperoxy compounds may vary broadly, depending on the kind of substrateand of the employed bleaching procedure, e.g. in the range of 0.1 to 20%by weight peroxy compound (preferably hydrogen peroxide) referred to drysubstrate, in particular 0.2 to 10%, preferably 0.5 to 5% hydrogenperoxide, referred to dry substrate. For the bleaching of textilematerial according to impregnation methods, the textile material isadvantageously impregnated with the bleaching liquor (e.g. at 15 to 40°C.) and the impregnated goods may then be stacked or rolled up andallowed to dwell in the cold (e.g. at 15 to 40° C.) or be subjected to aheat-treatment (e.g. at 80-120° C., preferably 90-105° C.), e.g.according to the hot dwell (pad-roll) process (e.g. at 80-100,preferably 90-100° C.) or according to the pad-steam process (e.g. at95-105° C., preferably 96-103° C.), and may then be rinsed and dried.Hot bleaching takes place advantageously at 80-98° C. and immersionbleaching advantageously at 50-90° C., preferably 70-80° C. At aliquor-to-goods ratio of advantageously 5:1 to 2:1, the pH-value of thebleaching bath is advantageously in the range of 8-14, preferably 9-12.

With the polymers (P) to be employed according to the invention, theremay be produced very concentrated and stable alkaline stock solutionsand in the peroxide bleaching of cellulose-containing fibrous materialthere may be achieved optimum whiteness values, without it beingnecessary to employ other sequestering agents, which, however, does notexclude that other sequestering agents may additionally be employed inthe case that this should be desired for a certain process or substrate.The polymers (P) to be employed according to the invention are wellcompatible with other sequestrants and may be combined with inorganicsequestrants, e.g. borates or silicates, as well as with organicsequestrants, e.g. acid-modified mono- or polyamines, as mentioned aboveunder (G), or with oxyacid salts, such ashydroxyalkylidene-polyphosphonic acid derivatives, sodium gluconate,tartrate, citrate or -heptonate etc. After completion of the bleachingthe polymers (P2) or (P3) may be rinsed out or washed out, particularlyalso from the bleached. substrate. The polymers (P) are also readilybiologically degradable, so that they may be degraded in the enzymaticphase of the back-water depuration.

In the following Examples parts signify parts by weight and percentagessignify percentages by weight; the temperatures are indicated in degreesCelsius. The α-amylase employed in the following Examples is acommercially available α-amylase with an activity of 120 U/g [1 U is thequantitiy of enzyme which at 37° C., pH 5.6 and a calcium content of0.0043 M in the liquor, degrades to dextrine 5.26 g of soluble starch(Merck, Amylum Solubile Erg.B. 6, charge 9947275) per hour, determinedon a solution of 6.95 g of dry starch/liter]. There are employed thefollowing aqueous solutions:

solution (m)=35% hydrogen peroxide solution

solution (n)=19.5% solution of 2-chloroacrylic acid sodium salt

solution (p)=30% sodium hydroxide solution

solution (q)=solution of 18.45 parts of MgCl₂.6H₂O in 1000 parts ofwater.

EXAMPLE 1

100.0 parts of native potato starch, dispersed in 100.0 parts of water,are treated during 60 minutes at pH 6.8 and at 90° C. with 17.5 parts ofan aqueous 5% solution of an α-amylase with an activity of 120 U/g. Thenat 75° C. 23.2 parts of sulphuric acid and 9.7 parts of solution (m) areadded and subsequently 112.3 parts of solution (n) are fed-in during 50minutes. At 75-80° C. there are now further simultaneously added during100 minutes 453.3 parts of solution (n) and 38.9 parts of solution (m)and stirring is continued for 4 hours at 75-80° C. After this 166.0parts of water (with traces of monomer) are distilled off under vacuum,then the pH-value is adjusted to 7.0 with solution (p), the mixture iscooled to room temperature, the total weight is adjusted with water to900.0 parts of final product and the final product is discharged.

EXAMPLE 2

The procedure is carried out as described in Example 1, with thedifference that there is carried out no enzymatic treatment, but thestarch suspension is directly heated to 75° C. and there are onlyemployed half of the respective amounts of solution (m).

EXAMPLE 3

The procedure is carried out as described in Example 2, with thedifference that instead of 100.0 parts of native potato starch,dispersed in 100 parts of water, there are employed 50.0 parts ofamylopectine from corn, dispersed in 50 parts of water.

EXAMPLE 4

The procedure is carried out as described in Example 3, with thedifference that instead of amylopectine from corn there is employedamylose from potato starch.

EXAMPLE 5

100.0 parts of native potato starch, dispersed in 100.0 parts of water,are treated with 21.9 parts of sulphuric acid and 3.3 parts of solution(m) and heated to 75° C. Then 67.7 parts of solution (n) are addedwithin 45 minutes, the temperature being kept between 75 and 77° C.Subsequently 365.7 parts of solution (n) and 6.6 parts of solution (m)are added simultaneously at the same temperature (75-77° C.) within 90minutes. After 4 hours of further stirring 166.0 parts of water (withtraces of monomer) are distilled off under vacuum, then 144.3 parts ofsolution (p) are regularly added dropwise within 2 hours, the pH beingabout 9 to 11. Stirring is now continued during 12 hours at 95° C. andthen there is cooled to 40° C. The pH-value is then about 6.5±0.5. Now26.9 parts of phthalic acid anhydride and then 53.5 parts of solution(p) are furter added and further, as soon as the anhydride hasdissolved, 73.2 parts of water. Subsequently the product is dischargedover a Meraklon-cloth-filter with the aid of filtering earth. There isobtained a clear, transparent, dark-brown polymer solution.

EXAMPLE 6

The procedure is carried out as described in Example 1 with thedifference that instead of 100.0 parts of native potato starch dispersedin 100.0 parts of water, there are employed 50.0 parts of corn starchsuspended in 50.0 parts of water, and instead of 17.5 parts of theaqueous 5% α-amylase-solution there are employed 17.5 parts of anaqueous 1% solution of the same α-amylase and the enzymatic treatment isstopped after 30 minutes by addition of sulphuric acid and there isemployed only half of the respective amounts of solution (m).

EXAMPLE 7

The procedure is carried out as described in Example 5 up to thedistilling-off of water (with traces of monomer), but after the 4 hoursof further stirring there is cooled from 75-77° C. to 40° C and between40 and 50° C. there are added dropwise within 2 hours 121.11 parts of anaqueous 50% potassium hydroxide solution. Now there is heated to 100° C.and without vacuum 114.50 parts of water are distilled off within 15hours. Now there is cooled to 60-65° C. and, in order to improve the owncolour, 18.61 parts of solution (m) are added and after further stirringfor 2 hours at 60-65° C., there is cooled to room temperature andsubsequently the pH-value is adjusted to 7.0 with a minimal quantity ofpotassium hydroxide solution. Now 70 parts of an aqueous 40% solution ofnitrilotriacetic acid trisodium salt are further added and the productis discharges over a Meraklon-cloth-filter with the aid of filteringearth.

EXAMPLE 8

The procedure is carried out as described in Example 7, but instead of114.50 parts of water there are now distilled off 57.0 parts of waterwithin 7 hours. After the distilling-off of the water there is cooled toroom temperature and the pH is adjusted to 7.0. Now 15 parts ofmagnesium chloride hexahydrate are further added thereto andsubsequently the product is discharged over a Meraklon-cloth-filter withthe aid of filtering earth.

EXAMPLE 9

The procedure is carried out as described in Example 7, but instead of70 parts of an aqueous 40% solution of nitrilotriacetic acid trisodiumsalt, 35 parts of triethanolamine are added dropwise.

EXAMPLE 10

The procedure is carried out as described in Example 8, but in additionto the 15 parts of magnesium chloride hexahydrate 35 parts of an aqueous40% solution of nitrilotriacetic acid trisodium salt are further addeddropwise thereto.

EXAMPLE 11

100.0 parts of native potato starch, dispersed in 70.0 parts of waterare treated with 44.3 parts of citric acid monohydrate and heated to 95°C. After three hours at this temperature the mixture is cooled to 75° C.and then 528.8 parts of solution (n) and 22.7 parts of solution (m) aresimultaneously added during 150 minutes. After 4 hours of furtherstirring at 75-80° C. 55.5 parts of water are distilled off undervacuum. Then the pH is set to 7.0 with the aid of about 141.8 parts ofsolution (p) at about 50-60° C., then about 2.4 parts of solution (m)are further added, the mixture is cooled to room temperature and thetotal weight is set with water to 868.0 parts of final product.

EXAMPLE 12

The procedure is carried out as described in Example 11, but there areemployed 22.6 parts of sulphuric acid instead of 44.3 parts of citricacid monohydrate. By this there are afforded about 123.1 parts ofsolution (p) in order to set the pH-value to 7.0. The total weight ofthe final product is also set to 868.0 parts.

Application Example A

100% cotton, desized and boiled-off, is padded to a pick-up of 100% withthe following bleaching liquors:

10 ml/l of solution (q) (corresponding to a bleaching liquor of 5° dH)

4 ml/l of wetting agent (concentrated solution of phosphoric acidpartial esters of partially di-oxyethylated C₈₋₁₁-alcohols, sodium salt)

x ml/l of product according to Example 1

15 ml/l of solution (p)

30 ml/l of solution (m).

Then the padded fabric is allowed to dwell according to the pad-rollprocedure during 90 minutes at 95° C. Subsequently it is rinsed warm andcold, up to a neutral pH.

x=5, 10 or 15.

There are obtained high effects of degree of whiteness, which are fairlydelimited, depending on the product quantity.

Application Example B

The procedure is carried out as described in Application Example A, butin the bleaching liquor there are employed

20 ml/l of solution (p) (instead of 15) and

40 ml/l of solution (m) (instead of 30)

and instead of the pad-roll there is used the pad-steam procedure(treatment at 103° C. during 20 minutes). There are also obtained highbleaching effects.

Application Example C

The procedure is carried out as described in Application Example B butthe bleaching liquor is produced from a five-fold reinforcing liquor:

First there is produced a reinforcing liquor of

10 ml/l of solution (q)

20 ml/l of wetting agent

100 ml/l of solution (p)

200 ml/l of solution (m)

5·x ml/l of the product according to Example 1

of which one fifth (200 ml) is diluted with 800 ml of a solution of 10ml/liter of solution (q). The diluted bleaching liquor is then employedas in Application Example B. There are obtained similarly good whiteeffects.

Analogously as the product according to Example 1 there are employed ineach of Application Examples A, B and C the products of Examples 2 to12.

What is claimed is:
 1. A water soluble alkali metal salt of(co)poly-α-hydroxyacrylic acid based polymer made by free radicalpolymerization in acidic medium followed by reaction with a base andcomprising; (s) at least one carbohydrate unit; and, (a) at least oneunit which is an alkali metal salt of 2-hydroxy-2-carboxylic acidethylene-1,2-unit; and optionally (b) a unit (b), which is a unitderived from polymerization of an α,β-ethylenically unsaturatedaliphatic carboxylic acid monomer having 3 to 6 carbon atoms, andfurther where unit denoted as (s) in the polymer ranges from 16 mole %to 67 mole %.
 2. The polymer according to claim 1, where the polymerfurther comprises a unit (b).
 3. The polymer according to claim 2, wherethe concentration of unit (b) is up to 50 mole percent of the totalmolar concentration of (a)+(b) in the polymer.
 4. The polymer accordingto claim 1, where the unit (a) is at least 50 mole percent to 100 molepercent of the polymer of the total molar concentration of units(a)+(b).
 5. The polymer according to claim 1, where the carbohydrateunit denoted as (s) is selected from a group consisting ofmonosaccharides, oligosaccharides, polysaccharides, modifiedsaccharides, starches and mixtures thereof.
 6. A polymer according toclaim 1, in which the α-hydroxyacrylic acid units are in partlactonized.
 7. A magnesium complex of the polymer of claim
 6. 8. Amagnesium complex of the polymer according to claim
 1. 9. Aqueousdilution of a polymer comprising the polymer of claim 6 and water. 10.Concentrated aqueous composition comprising a complex according to claim8 and water.
 11. Concentrated aqueous, alkaline, stabilizer-containingsolutions comprising: a complex according to claim 8; alkali metalhydroxide; and water.
 12. Concentrated aqueous, alkaline,stabilizer-containing solutions which are alkaline stock solutions orreinforcing liquors for the peroxide bleach, comprising a complexaccording to claim 8 with an alkalinity of 0.2N to 8N NAOH.
 13. Alkalineperoxide bleaching liquors comprising a complex according to claim 8, analkali and a peroxide-based bleaching agent with an alkali content of0.4% to 5% of NaOH.
 14. An aqueous solution composition comprising analkali metal salt of water-soluble (co)poly-α-hydroxyacrylic acid basedpolymer of claim 1, an alkali metal hydroxide and water.
 15. Thecomposition according to claim 14, further containing at least one ofthe following components; (E) at least one water-soluble magnesium salt,and, (F) at least one surfactant.
 16. The composition according to claim14, where the polymer is a sodium or potassium salt.
 17. The compositionaccording to claim 14, where the polymer is a magnesium complex salt ora mixture of sodium salt and magnesium complex salt.
 18. The compositionaccording to claim 14, where the alkali metal hydroxide is sodiumhydroxide or potassium hydroxide.
 19. The composition according to claim14, where the carbohydrate unit denoted as (s) is selected from a groupconsisting of monosaccharides, oligosaccharides, polysaccharides,modified saccharides and starches and mixtures thereof.
 20. A processfor the alkaline bleaching of cellulosic textile material in textilepretreatment or of paper comprising adding the composition from claim14.
 21. The composition according to claim 14, further comprising aperoxide-based bleaching agent.
 22. The composition according to claim21, with an alkalinity of 0.2N to 8N NaOH.
 23. The composition accordingto claim 21, with an alkali content of 0.4% to 5% of NaOH.
 24. Thecomposition according to claim 21, further comprising a water solublemagnesium salt.
 25. A process for alkaline bleaching of cellulosictextile material in textile pretreatment or paper comprising adding thecomposition from claim
 24. 26. A process for alkaline bleaching ofcellulosic textile material in textile pretreatment or paper, comprisingadding the composition from claim
 21. 27. A process according to claim26 for the alkaline bleaching of textile material or paper byimpregation methods.